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• First Name + Last Name + Email
• Last Name + Email (depending on if you deal with Families that share email addresses - may not be useful). 
• First Name + Last Name + Phone (or Mobile)
• First Name + Last Name + Street
• Account Name
• Account Name + Phone
• Account Name + Street + City

Create your own Duplicates

You know that great feature in Classic named Merge Accounts where you could just pick any two or three Accounts with similar names and merge them. You know that great feature in Classic on the Contact Related List where you can mere Contacts? Both of these aren't in Lightning, so unless you are fortunate enough to use the Nonprofit Success Pack - NPSP and their excellent Contact Merge function, then you're out of luck, right? Well not quite... but it's not great. 

Announced in #Winter18 is the ability to create your own Duplicate Record Sets and merge them yourself

Duplicate Reporting

When you set Report on Standard Salesforce Duplicate Rules, it's not clear at all what Report does. 

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